US marks six months with no executions

Lethal injection is the most commonly used method of execution in the US.

California Department of Corrections: AAP

The United States has marked its sixth consecutive month with no executions of prisoners, its longest such period since 1982.

But experts say the death penalty could make a swift return once questions about lethal injection are resolved.

The last execution took place on September 25, when 48-year-old Michael Richard was put to death for the rape and murder of a woman 20 years earlier.

He was executed by lethal injection, the method most commonly used.

Just hours before Richards was pronounced dead by a Texas physician, the US Supreme Court had announced it would examine the legality of the lethal injection method.

The court is considering arguments from several death row inmates, led by a pair from Kentucky, that execution by lethal injection violates the US Constitution, which prohibits "cruel and unusual punishment".

Richards' case was rushed through after a Texas court refused to stay open to hear his appeal, angering those who oppose the death penalty in the state which has convicted the highest number of prisoners since 1976.

According to the Death Penalty Information Centre, only one more execution is planned this year, that of a convict in Louisiana in July.

The Supreme Court is expected to announce its ruling by the end of June on the three-part injection method by which the first part sedates the inmate, the second paralyses the muscles and the third stops the heart.

Around two-thirds of Americans favour the death penalty, according to the DPIC, in a country where 3,260 detainees are presently on death row.